/*
 * Copyright (C) 2011 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.inject.internal;

import static com.google.common.base.Preconditions.checkState;

import com.google.inject.Key;
import com.google.inject.ProvidedBy;
import com.google.inject.Provider;
import com.google.inject.internal.InjectorImpl.JitLimitation;
import com.google.inject.spi.Dependency;

/**
 * An {@link InternalFactory} for {@literal @}{@link ProvidedBy} bindings.
 * 
 * @author sameb@google.com (Sam Berlin)
 */
class ProvidedByInternalFactory<T> extends ProviderInternalFactory<T> implements DelayedInitialize {

    private final Class<?> rawType;
    private final Class<? extends Provider<?>> providerType;
    private final Key<? extends Provider<T>> providerKey;
    private BindingImpl<? extends Provider<T>> providerBinding;
    private ProvisionListenerStackCallback<T> provisionCallback;

    ProvidedByInternalFactory(Class<?> rawType, Class<? extends Provider<?>> providerType, Key<? extends Provider<T>> providerKey) {
        super(providerKey);
        this.rawType = rawType;
        this.providerType = providerType;
        this.providerKey = providerKey;
    }

    void setProvisionListenerCallback(ProvisionListenerStackCallback<T> listener) {
        provisionCallback = listener;
    }

    public void initialize(InjectorImpl injector, Errors errors) throws ErrorsException {
        providerBinding = injector.getBindingOrThrow(providerKey, errors, JitLimitation.NEW_OR_EXISTING_JIT);
    }

    public T get(Errors errors, InternalContext context, Dependency dependency, boolean linked) throws ErrorsException {
        checkState(providerBinding != null, "not initialized");

        context.pushState(providerKey, providerBinding.getSource());
        try {
            errors = errors.withSource(providerKey);
            Provider<? extends T> provider = providerBinding.getInternalFactory().get(errors, context, dependency, true);
            return circularGet(provider, errors, context, dependency, provisionCallback);
        } finally {
            context.popState();
        }
    }

    @Override
    protected T provision(javax.inject.Provider<? extends T> provider, Errors errors, Dependency<?> dependency, ConstructionContext<T> constructionContext) throws ErrorsException {
        try {
            Object o = super.provision(provider, errors, dependency, constructionContext);
            if (o != null && !rawType.isInstance(o)) {
                throw errors.subtypeNotProvided(providerType, rawType).toException();
            }
            @SuppressWarnings("unchecked") // protected by isInstance() check above
            T t = (T) o;
            return t;
        } catch (RuntimeException e) {
            throw errors.errorInProvider(e).toException();
        }
    }
}
